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登封地区工程地质条件与评价

发布时间:2016-07-27 09:23:51 点击:

  登封地区工程地质条件与评价

  登封市位于河南省中西部,中岳嵩山南麓,嵩山在大地构造上处于华北古陆南缘,在公园范围内,连续完整地露出35亿年以来太古代,元古代,古生代,中生代和新生代五个地质历史时期的地层,地层层序清楚,构造形迹典型,被地质界称为“五代同堂”,实际上是一部完整的地球历史石头书。此次我的报告重点对登封地区的地质条件进行分析和评价。

  一、岩石情况

  登封地区三大岩类都有,岩浆岩,沉积岩,变质岩。

  登封地区岩浆岩中花岗岩较为显著。花岗岩是一种岩浆在地表以下凝却形成的火成岩,主要成分是长石和石英。花岗岩的语源是拉丁文的granum,意思是谷粒或颗粒。因为花岗岩是深成岩,常能形成发育良好、肉眼可辨的矿物颗粒,因而得名。花岗岩不易风化,颜色美观,外观色泽可保持百年以上,由于其硬度高、耐磨损,除了用作高级建筑装饰工程、大厅地面外,还是露天雕刻的首选之材。

  沉积岩中石灰岩较为显著。石灰岩简称灰岩,以方解石为主要成分的碳酸盐岩。有时含有白云石、粘土物质和碎屑矿物,有灰、灰白、灰黑、黄、浅红、褐红等色,硬度一般不大,与稀盐酸反应剧烈。石灰岩主要是在浅海的环境下形成的。石灰岩按成因可划分为粒屑石灰岩(流水搬运、沉积形成);生物骨架石 灰岩和化学、生物化学石灰岩。按结构构造可细分为竹叶状灰岩、状灰岩、团块状灰岩等。石灰岩的主要化学成分是碳酸钙易溶蚀,故在石灰岩地区多形成石林和溶洞,称为喀斯特地形。

  变质岩中石英岩和片麻岩较为显著。石英岩是石英含量大于85%的一种变质岩,一般是由砂岩或其他硅质岩石经过区域变质作用,重结晶而形成的。在岩浆附近,也可能是硅质岩石经过热接触变质作用而形成石英岩。主要矿物是石英,一般为浅色或白色,质密坚硬,但其颗粒常结成致密块状,肉眼不容易区分。石英岩一般为块状构造,粒状变晶结构,也含有少量的长石、绢云母、角闪石、辉石等,有各种颜色,硬度高,可以作为建筑材料或铁路的铺轨石。纯色颗粒细腻的可以作为工艺品雕刻原料。片麻岩是一种变质岩,而且变质程度深,具有片麻状构造或条带状构造,有鳞片粒状变晶,主要由长石、石英、云母等组成,其中长石和石英含量大于50%,长石多于石英。如果石英多于长石,就叫做"片岩"而不再是片麻岩

  二、崩塌

崩塌,指陡峻山坡上岩块、土体在重力作用下 ,发生突然的急剧的倾落运动。多发生在大
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于60°~70°的斜坡上。崩塌的物质,称为崩塌体。崩塌体为土质者,称为土崩;崩塌体为岩质者,称为岩崩;大规模的岩崩,称为山崩。当崩塌产生在河流、湖泊或海岸上时,称为岸崩。崩塌可以发生在任何地带,山崩限于高山峡谷区内。

  岩土类型、地质构造、地形地貌三个条件,统称地质条件,它是形成崩塌的基本条件。登封地区是典型的易发生崩塌的地区。如何防治崩塌,遮挡:即遮挡斜坡上部的崩塌物。这种措施常用于中、小型崩塌或人工边坡崩塌的防治中,通常采用修建明硐、棚硐等工程进行,在铁路工程中较为常用。拦截:对于仅在雨后才有坠石、剥落和小型崩塌的地段,可在坡脚或半坡上设置拦截构筑物。如设置落石平台和落石槽以停积崩塌物质,修建挡石墙以拦坠石等,也常用于铁路工程。支挡:在岩石突出或不稳定的大孤石下面修建支柱、支挡墙或用废钢轨支撑。护墙、护坡:在易风化剥落的边坡地段,修建护墙,对缓坡进行水泥护坡等。一般边坡均可采用镶补沟缝:对坡体中的裂隙、缝、空洞,可用片石填补空洞,水泥沙浆沟缝等以防止裂隙、缝、洞的进一步发展。刷坡、削坡:在危石孤石突出的山嘴以及坡体风化破碎的地段,采用刷坡技术放缓边坡。排水:在有水活动的地段,布置排水构筑物,以进行拦截与疏导。

  三、滑坡

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斜坡的局部稳定性受破坏,在重力作用下,岩体或其他碎屑沿一个或多个破裂滑动面向下做整体滑动的过程与现象。产生滑坡的基本条件是斜坡体前有滑动空间,两侧有切割面。例如登封地区,特别是丘陵山区,最基本的地形地貌特征就是山体众多,山势陡峻,土壤结构疏松,易积水,沟谷河流遍布于山体之中,与之相互切割,因而形成众多的具有足够滑动空间的斜坡体和切割面。广泛存在滑坡发生的基本条件,滑坡灾害相当频繁。

  防治措施:

  1、消除和减轻地表水和地下水的危害

  滑坡的发生常和水的作用有密切的关系,水的作用,往往是引起滑坡的主要因素,因此,消除和减轻水对边坡的危害尤其重要,其目的是:降低孔隙水压力和动水压力,防止岩土体的软化及溶蚀分解,消除或减小水的冲刷和浪击作用。具体做法有:防止外围地表水进入滑坡区,可在滑坡边界修截水沟;在滑坡区内,可在坡面修筑排水沟。在覆盖层上可用浆砌片石或人造植被铺盖,防止地表水下渗。对于岩质边坡还可用喷混凝土护面或挂钢筋网喷混凝土。排除地下水的措施很多,应根据边坡的地质结构特征和水文地质条件加以选择。常用的方法有:1,水平钻孔疏干;2,垂直孔排水;3,竖井抽水;4,隧洞疏干;5,支撑盲沟。

  2、改善边坡岩土体的力学强度

通过一定的工程技术措施,改善边坡岩土体的力学强度,提高其抗滑力,减小滑动力。常用的措施有:1,削坡减载;用降低坡高或放缓坡角来改善边坡的稳定性。削坡设计应尽量削减不稳定岩土体的高度,而阻滑部分岩土体不应削减。此法并不总是最经济、最有效的措施,要在施工前作经济技术比较。2,边坡人工加固;常用的方法有:1,修筑挡土墙、护墙等支挡不稳定岩体;2,钢筋混凝土抗滑桩或钢筋桩作为阻滑支撑工程;3,预应力锚杆或锚索,适用于加固有裂隙或软弱结构面的岩质边坡;4,固结灌浆或电化学加固法加强边坡岩体或土体的强度;5, SNS边坡柔性防护技术等。
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  登封五日实习结束了,在这里我首先要感谢学校为我们安排了这次实习课程,没有学校的组织安排,我们就没有此次实习的机会。此外,还要感谢唐东旗、高均昭、徐进、杨真真,四位老师的指导与照顾。

  通过此次野外实习,我不仅对课本的基础知识有了更深理解,而且观察到各种地质地貌现象并积累了大量的地质地貌方面的材料,更重要的是通过实践我学到了许多课本上没有的知识,实现了理论与实践的结合。

  Engineering geological conditions and evaluation in Dengfeng area

  Dengfeng city is located in the central and western part of Henan Province, Zhongyue Songshan south, Songshan in tectonic in the southern margin of the North China paleocontinent, within the boundaries of the park, continuous completely exposed 3.5 billion years since the Archean, Proterozoic, Paleozoic, strata of Mesozoic era and the new generation of five geological history period, sequence stratigraphy clear, typical tectonic trace, is referred to as the "five generations of geologists is actually a complete history of earth stone book. This report focuses on the analysis and evaluation of the geological conditions in Dengfeng area.

  First, the rock condition

  The Dengfeng area has three main types, magmatite, sedimentary rocks and metamorphic rocks.

  The granite in Dengfeng area is more significant. Granite is a kind of igneous rock formed by the formation of magma below the surface of the earth's surface, the main component is feldspar and quartz. Granite etymology is the Latin granum, mean grain or granule. Because granite is often formed plutonic rocks, mineral particles are well developed, recognizable, hence the name. Granite is not easily weathered, beautiful color, appearance and color can be maintained for more than a hundred years, due to its high hardness, abrasion resistance, used as a senior architectural engineering, the hall floor, in addition or open-air sculpture of the first choice material.

  Limestone is more significant in sedimentary rock. Limestone, carbonate rock, which is the main component of calcite. Sometimes contain dolomite, clay materials and detrital minerals, gray, gray, dark gray, yellow, pink and brown red color, hardness is generally small with dilute hydrochloric acid reaction violent. Limestone is formed mainly in the shallow water environment. The limestone can be divided into the formation of granular limestone (water transport, sediment formation); biological skeleton limestone and chemical, biological and chemical limestone. According to the structure, the structure can be divided into the bamboo leaf like limestone, the limestone, the lump limestone and so on. The main chemical composition of the limestone is calcium carbonate easily dissolved, so in the limestone area formed stone forest, karst cave, karst topography.

  In the metamorphic quartzite gneiss and more significant. The quartz rock is a metamorphic rock with a quartz content of more than 85%, which is usually formed by the regional metamorphism and recrystallization of sandstone or other silica rocks. In the vicinity of magma, it is also possible that the silica rock formed by thermal contact metamorphism. The main mineral is quartz, generally light colored or white, dense and hard, but its particles often form a dense block, the naked eye is not easy to distinguish. Quartzite is generally block structure, granoblastic crystal structure, also contains a small amount of feldspar, mica, amphibole, clinopyroxene etc., a variety of color, high hardness can as building materials or railway track laying stone. Solid fine particles can be used as carving handicraft raw materials. Gneiss is a kind of metamorphic rocks, and metamorphic degree, with gneissic structure or banded structure, scale granoblastic, mainly composed of feldspar, quartz and mica, which content of feldspar and quartz are greater than 50%, feldspar than quartz. If more than quartz feldspar, called schist instead of gneiss

  Two, collapse

  A steep hillside collapse, rock and soil under the action of gravity, a sudden sharp falling movement. Occurred in more than 60 degrees to 70 degrees on the slope. The collapse of the material, known as the collapse of the body. The collapse of soil, called for rock landslides; landslides, rockfall called; massive rockfall, called landslide. When a collapse is produced on a river, lake, or shore, it is called a bank collapse. Collapse can occur in any area, limited to the mountain canyon area landslide.

  Three conditions, geological conditions, geological conditions, geological conditions, it is the basic conditions for the formation of the collapse of the rock and soil type, geological structure and topography. The Dengfeng area is a typical area which is prone to collapse. How to prevent and control the collapse and shelter: the collapse of the upper part of the slope. This measure is commonly used in the prevention and control of the collapse of the medium or small scale or artificial slope, usually by the construction of the tunnel, shed tunnel and other projects, in the railway engineering is more commonly used. Interception: for only after the rain is falling stone, spalling and small collapse lots, the toe or Banpo setting block structures. Such as setting the rockfall platform and trough to stop product collapse rockfall material, building wall Elam Dropstone, is also commonly used in railway engineering. Retaining: pillar, retaining wall or scrap rail support built in the rocks below prominent or unstable large boulders. Wall, slope protection: the construction of wall in slope area, easy weathering, cement slope on slope. The general slope can use inlay groove seam of cracks in slope, crevices, holes, fill the hole of available rubble, cement mortar groove joint to prevent cracks, joints and holes further development. The slope, slope in dangerous rock slope and prominent boulder Hill weathering area, the slope slope technology slowdown. Drainage: in a lot of water activity, the layout of drainage structures, in order to intercept and ease. Three, landslide

  The local stability of the slope is destroyed, and the process and phenomenon of the whole sliding along one or more of the broken rock and other debris are under the action of gravity. The basic condition for the production of a landslide is that there is a sliding space in front of the slope, and there are cutting surfaces on both sides. Such as the Dengfeng area, especially the upland and a mountainous area, the basic landform is many mountains, steep mountains, loose soil structure, easy water, streams and river valleys throughout the mountain, and cut each other, thus forming numerous has enough space for the sliding slope and cutting surface. The basic condition of landslide occurrence is widespread, and the landslide disaster is quite frequent.

  Prevention and control measures:

  1, eliminate and reduce the hazards of surface water and groundwater

  The occurring of landslides often and the role of water has close relationship, the role of water, often is one of main factors that caused a landslide. As a result, the elimination and reduce the damage of water on slope is particularly important, the purpose is: reduce the pore water pressure and dynamic water pressure, prevent rock and soil softening dissolution and decomposition is used to eliminate or reduce water erosion and shock wave effect. Specific practices are: to prevent the surface water into the surface of the landslide area, can be in the landslide boundary repair ditch; in the landslide area, can be built on the slope of drainage ditch. The cover is available mortarrubble or artificial vegetation cover to prevent infiltration of surface water. The rock slope can also spray concrete facing or hanging mesh reinforced shotcrete. Many measures to eliminate groundwater should be selected according to the geological structure characteristics and hydrogeological conditions of the slope. Commonly used methods are: 1, horizontal drilling and drainage; 2, vertical hole drainage; 3, vertical shaft pumping; 4, tunnel drainage; 5, support blind ditch.

  2, improve the mechanical strength of rock and soil slope

  Through a certain engineering measures, improve the mechanical strength of rock and soil slope, improve its anti sliding force, reduce the sliding force. The commonly used measures are: 1, cutting slope and reducing load; reduce the slope height or slope angle to improve the stability of the slope. Cut slope design should try to reduce the height of unstable rock and soil mass, and the resistance of the soil should not be cut. This method is not always the most economic and effective measures, to make economic and technical comparison before construction. 2, artificial slope reinforcement; commonly used methods are: 1, the construction of retaining walls, parapet walls support unstable retaining rock; 2, reinforced concrete anti slide piles or reinforced pile as anti slide support engineering; 3, prestressed anchor or anchor for fractured and weak structure plane in rock side slope to reinforce; 4, consolidation grouting or electrochemical consolidation method reinforcing the slope rock or soil strength; 5, SNS slope flexible protection technology and so on.

  Dengfeng five, the end of the internship, here I would like to thank the school for us to arrange the internship program, no school organization arrangements, we will not have the opportunity to practice. In addition, would also like to thank Tang Dongqi, Gao Junzhao, Xu Jin, Yang Zhenzhen, four teacher's guidance and care.

  Through the field internship, I not only the basic knowledge of textbooks have deeper understanding, and observed various geological or geomorphological phenomena and accumulated a lot of geological materials, the more important is through practice I learned many textbooks do not have the knowledge, to achieve a reasonable combination of theory and practice.